IBM Langflow OSS 1.0.0 through 1.10.3 contain an authorization bypass vulnerability in the MemoryComponent that allows authenticated users to access chat history of other users via sessionid collision. The MemoryComponent.retrievemessages and storemessage methods filter on sessionid without validating flowid or userid ownership, enabling cross-user information disclosure through multiple authenticated API endpoints including /api/v1/run/, /api/v1/responses, and /api/v2/workflow/. This vulnerability only affects multi-user deployments with LANGFLOWAUTOLOGIN=False.